This blog is a little effort to make biotechnology concepts simplified to all the students in the degree classes from all the universities.I took the initiative to make concise and well formulated notes supported with the diagrams.I have struggled a lot in making notes and searching for the concepts by digging library books and surfing various sites. All i want is to create one place where you can look up to biotechnology notes and rely upon them as i have put up a lot of effort on them.

Monday, 6 February 2012

Facts About DNA

Facts About DNA

DNA stands for deoxyribonucleic acid.

DNA is part of our definition of a living organism.

DNA is found in all living things.

DNA was first isolated in 1869 by Friedrich Miescher.

James Watson and Francis Crick figured out the structure of DNA.

DNA is a double helix.

The structure of DNA can be likened to a twisted ladder.

The rungs of the ladder are made up of “bases”

Adenine (A) is a base.

Thymine (T) is a base.

Cytosine (C) is a base

Guanine (G) is a base.

A always pairs with T in DNA.

C also pairs with G in DNA.

The amount of A is equal to the amoun tof T, same for C and G.

A+C = T+G

Hydrogen bonds hold the bases together.

The sides of the DNA ladder is made of sugars and phosphate atoms.

Bases attached to a sugar; this complex is called a nucleoside.

Sugar + phosphate + base = nucleotide.

The DNA ladder usually twists to the right.

There are many conformations of DNA: A-DNA, B-DNA, and Z-DNA are the only ones found in nature.

Almost all the cells in our body have DNA with the exception of red blood cells.

DNA is the “blueprint” of life.

Chromosomal or nuclear DNA is DNA found in the nucleus of cells.

Humans have 46 chromosomes.

Autosomal DNA is part of chromosomal DNA but does not include the two sex chromsomes – X and Y.

One chromosome can have as little as 50 million base pairs or as much as 250 million base pairs.

Mitochondrial DNA (mtDNA) is found in the mitochondria.

mtDNA is only passed from the mother to the child because only eggs have mitochondria, not sperm.

There’s a copy of our entire DNA sequence in every cell of our body with one exception.

Our entire DNA sequence is called a genome.

There’s an estimated 3 billion DNA bases in our genome.

One million bases (called a megabase and abbreviated Mb) of DNA sequence data is roughly equivalent to 1 megabyte of computer data storage space.

Our entire DNA sequence would fill 200 1,000-page New York City telephone directories.

A complete 3 billion base genome would take 3 gigabytes of storage space.

If unwound and tied together, the strands of DNA in one cell would stretch almost six feet but would be only 50 trillionths of an inch wide.

In humans, the DNA molecule in a non-sex cell would have a total length of 1.7 metres.

If you unwrap all the DNA you have in all your cells, you could reach the moon 6000 times!

Our sex cells–eggs and sperm–have only half of our total DNA.

Over 99% of our DNA sequence is the same as other humans’.

DNA can self-replicate using cellular machinery made of proteins.

Genes are made of DNA.

Genes are pieces of DNA passed from parent to offspring that contain hereditary information.

The average gene is 10,000 to 15,000 bases long.

The segment of DNA designated a gene is made up of exons and introns.

Exons have the code for making proteins.

Introns are intervening sequences sometimes called “junk DNA.”

Junk DNA’s function or lack thereof is a source of debate.

Part of “junk DNA” help to regulate the genomic activity.

There are an estimated 20,000 to 25,000 genes in our genome.

In 2000, a rough draft of the human genome (complete DNA sequence) was completed.

In 2003, the final draft of the human genome was completed.

The human genome sequence generated by the private genomics company Celera was based on DNA samples collected from five donors who identified themselves only by race and sex.

If all the DNA in your body was put end to end, it would reach to the sun and back over 600 times (100 trillion times six feet divided by 92 million miles).

It would take a person typing 60 words per minute, eight hours a day, around 50 years to type the human genome.

If all three billion letters in the human genome were stacked one millimeter apart, they would reach a height 7,000 times the height of the Empire State Building.

DNA is translated via cellular mechanisms into proteins.

DNA in sets of 3 bases, called a codon, code for amino acids, the building blocks of protein.

Changes in the DNA sequence are called mutations.

Many thing can cause mutations, including UV irradiation from the sun, chemicals like drugs, etc.

Mutations can be changes in just one DNA base.

Mutations can involve more than one DNA base.

Mutations can involve entire segments of chromosomes.

Single nucleotide polymorpshisms (SNPs) are single base changes in DNA.

Short tandem repeats (STRs) are short sequences of DNA repeated consecutively.

Some parts of the DNA sequence do not make proteins.

Genes make up only about 2-3% of our genome.

DNA is affected by the environment; environmental factors can turn genes on and off.

There are many ways you can analyze your DNA using commercially available tests.

Paternity tests compare segments of DNA between the potential father and child.

There are other types of relationship testing that compares DNA between siblings, grandparents and grandchild, etc.

DNA tests can help you understand your risk of disease.

A DNA mutation or variation may be associated with a higher risk of a number of diseases, including breast cancer.

DNA tests can help you understand your family history aka genetic genealogy.

DNA tests can help you understand your ethnic make-up.

DNA can be extracted from many different types of samples: blood, cheek cells, urine.

DNA can be stored either as cells on a cotton swab, buccal brush, or frozen blood or in extracted form.

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About Me

Myself a researcher interested in the field of genomics and biotechnology. Apart from following my dreams i also like to engage myself in helping other newbies in the field of life sciences. This blog is just a beginning to help budding scientists; who can get full fledged notes on biotech concepts. i have tried to make concise, thoroughly explained and supported with diagrams wherever necessary.This blog helps you avoid surfing websites for the conceptual notes. I am open to the suggestions and improvements!!! Good luck and Happy learning!!!